Gas octaning rating results and other comments!

[fivepointohman]

Ok so I ran 3 tanks of various gasoline of various grades for a total of 6 tank fulls, 1 take was 89 octane, got 450 to a tank, next tank was 87 octane I ran about 350 on that tank at 65mph highway ( all these readings are highway ) 93 ot me close to 400. I ran 93 in the city of myrtle beach and was averaging 15.4 MPG... ( racing the 2004 rx8 which I smoked hard, and the turbo neon ) didnt help that tank out. best was way home with the issues at 521 Miles to a tank of 89 with 25.7 Miles per gallon average. So seems to me for my northstar it likes 89 the best.

As for oil usage, out of 1700 miles, 1 quart of engine oil was needed. total mileage 1829 miles round trip, came home changed the oil today looked clean as ever, but I changed it for giggles, drain that nastiness as its fresh in the oil table.

Coolant, used none full when i left and full when i got home, no overheating to report even in the hills of PA.

Overall I am happy, Minus my ECM issues, which I think i figured out as a fuse panel corrosion issue, all is well. I have a slight vibration that is developed at 60MPH and up, seemed to start after I shut the car off at a rest stop and then started again. Hoping for wheel balance, not CV joints. Keep everyone posted there. Thanks for all the help with the road trip post. I think its great that I diagnosed at pretty much cleared the ECM and figured out my issue all while steady at 65MPH on highway 81 with my laptop and my blackberry and buddy doing all the typing and reading! Thanks guys!

[JohnnyG]

I think you're doing VERY well. Your MPG experiment lacks a lot of details (usually called scientific controls) but I think we all get the point......run 89 in that car and don't race any ricers!

As to you're tire vibration. I think you'll find it to be most noticeable at speeds from 68 to 72. If that is the case, please let us know.

The COMMON 68 -72 shakes are caused by out of round tires (and they don't need to be out by very much!). That's the good news. The fix can be simple, or it can be difficult. The final answer is called "Road Force Balance". Much has been written here on the subject, and a lot of it by me. Search the archives first.